Two-thirds of the students are...

[neb090]

1. Two-thirds of the students are from rich families.
2. Two-thirds of the population is immigrants.
3. Two-thirds of the information is worth referencing.
4. Two-thirds is a number.

Are they all correct?

 

[jutfrank]

Finish all the sentences.

 

[neb090]

Finish all the sentences.

Sorry, I have done it.

 

[jutfrank]

Only sentence 2 is incorrect.

(I won't quibble about the factuality of sentence 4.)

 

[neb090]

Only sentence 2 is incorrect.

(I won't quibble about the factuality of sentence 4.)

Hi, jutfrank,

What do you mean when you say "I won't quibble about the factuality of sentence 4."

Do you mean sentence 4 can be considered a complete sentence?

 

[jutfrank]

What do you mean when you say "I won't quibble about the factuality of sentence 4."

Don't worry about this. It's not important.

Do you mean sentence 4 can be considered a complete sentence?

Yes, it's a complete sentence.

 

[Rover_KE]

I’ll quibble and say ‘Two-thirds is a fraction.’

 

[PaulMatthews]

1. Two thirds of the students are from rich families.
2. Two thirds of the population is immigrants.
3. Two thirds of the information is worth referencing.
4. Two thirds is a number.

So it's a question about number agreement.

Fractions like "thirds" belong to the noun category since they take determiners, usually cardinal numbers like "two" in your examples.

Verbs usually agree with the number of the head noun phrase, which here is the plural "two thirds". However, fractions are best analysed as 'number transparent in that it is the noun phrase that is complement of "of" that determines the grammatical number of the whole noun phrase.

In that analysis, the plural noun "students" in 1. takes the plural verb "are", while the singular nouns "population" and "information" in 2. and 3. take singular "is".

Note: for those who treat "population" as a collective noun, plural "are" in 2. may be preferred, especially because it matches the plural complement "immigrants".